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RE: FOCUS II ARF construction by-the-numbers

Don, I'm sorry if this topic has been dicsussed before but I couldn't find it. Would it be OK to just glue down the top canopy rather than have top access? All my servos went in from the bottom anyway. If you glue the top on it gives more options for mounting tank and receiver. It also doesn't rattle, fall off in flight, may strengthen the fuse, etc. I just know there is something I'm not thinking of so I wanted to ask for input before sealing up the top of the plane. I got along fine with the Focus I that didn't open on top. Craig

RE: FOCUS II ARF construction by-the-numbers

Hi
i have the Onyx ...European copy off the focus 1 as i understand...but the point it has the access to the radio room from the bottom.
I think its better to have it from the top because a couples off things ... firsts and most important u have to open the radio room every time u have been out flying , thats gives you an easy possibility to get a quick look in that area and u also see the fuel tank , this easter on my airfield the snow has been melting and made the grass very wet and the water that the wheels splashing up is hitting the long pipe channel and some off that water was finding its way in to the balsa on the edges under there, but i think the most important is the easy access to the radio area.

RE: FOCUS II ARF construction by-the-numbers

Yes the Onxy is a very close copy except that it uses a completely different/ far thicker airfoil.
The underbelly access (very popular in the US until recently) used on the Focus 1 is just plain awfull.
Some years ago I bought a Piedmont Hydeout that came with the same arrangment. I sealed the belly pan and made acess through the canopy.
Lee didn't seem to have the slightest idea of what I was talking about at the time but later on the temptation (basically a modified Hydeout ((waiting for the punches)) appeared with a similar set-up.

RE: FOCUS II ARF construction by-the-numbers

Got a chance to do some additional flying on the Focus a couple of weeks ago. The airplane still flies very well. I tried a 15.5x12 four blade propellor but did not really like the way it responded. It was actually too slow in the horizontals for my taste. The prop works well on the Brio, but for the Focus, it slows it down just a bit too much.
The 17x12 two blade works pretty well and will stay with that one. Any case, will be looking at selling the Focus soon. A great flying plane but will be moving on to another Brio.

RE: FOCUS II ARF construction by-the-numbers

ORIGINAL: Don Szczur

Got a chance to do some additional flying on the Focus a couple of weeks ago. The airplane still flies very well. I tried a 15.5x12 four blade propellor but did not really like the way it responded. It was actually too slow in the horizontals for my taste. The prop works well on the Brio, but for the Focus, it slows it down just a bit too much.
The 17x12 two blade works pretty well and will stay with that one. Any case, will be looking at selling the Focus soon. A great flying plane but will be moving on to another Brio.

Don

Don good talking to you this week at Nat's and glad you crash was minor and you and your son was unhurt.
I tried the 15.75 X13 3 blade on a Mintor 170 and really like the power and performance it made the Focus for me a much better plane.
Steve Maxwell

RE: FOCUS II ARF construction by-the-numbers

he 4 blade on the Focus was just a bit too much fan area up there for my tastes. I've tried this new prop 15.75 x 11 3 blade on the Brio with excellent results. Would be curious how that works on the Focus. It is re-pitched by Dave Lockhart. I also got a prototype 18.1x 11 which I would like to try on the Focus vs. the Brio.

RE: FOCUS II ARF construction by-the-numbers

Hi Don and all,

I've been flying my new Focus 2 and almost have it dialed in now except for the snap. I've got this thing doing a good snap but the only problem is it goes off tract about 15-20' or more when I snap. I tried cutting the rudder input by 50% and it didn't seem to help. I'm using a snap button and still have the ailerons elevators at 100% using Don's throws on high. The heading doesn't change much but boy does it move sideways when you snap. I was going to try less elev and aileron today but ran out of time to fly. Any idea's on this?

RE: FOCUS II ARF construction by-the-numbers

Hello Tim,

Try snapping without the button. It will give you more options to deal with the variables in a snap such as speed and wind. Plus you can try things like giving elevator first to get the break and then add the ail and rudder.

RE: FOCUS II ARF construction by-the-numbers

Fit the engine box. Trimmed 5/8 for a perfect fit. I prefer a little more down and right thrust. I built this in to try and get it a little closer to start out... I trimmed the right engine box side 1/16 less (9/16 rather then 5/8). Attached is the diagram with the Hyde ARI mount and YS 140DZ engine.

RE: FOCUS II ARF construction by-the-numbers

If interested, dimensions are below. I flew the YS 160 DZ in the FOCUS II at the 2004 NATS and the mount dimensions were identical, as were the applicable thrust measures. Double check your forward-to aft engine mount dimensions. They should be very close. Do this by tack-gluing in the firewall and mount in place with a couple of small drops of thick CA. If its ok, then mark, separate the firewall and glue in place.

RE: FOCUS II ARF construction by-the-numbers

Don with the 1.60 in the Focus did you find that throttle to rudder mix was required? Seems mine needs more right rudder at high throttle and less at low throttle even almost left. Thanks for being here.

RE: FOCUS II ARF construction by-the-numbers

Don,
I PM'd you again.
I don't come up with the same measurements.
Here is a pix of my Hyde Type A mount and YS 1.40 Sport.
I get approx 6.4" from back of mount to thrust washer.
I had already cut the firewall before you sent your reply.
I cut it by approx. 1".
I am at close to 1/32" spinner backplate to cowl spacing.
I will put a double sided sandpaper disk between the spinner and thrust washer per Dave Shadel's recommendations, that should get me to the recommended 1/16", but I don't think this is going to allow me to make any add'l side or down thrust adjustments.
One saving grace is I haven't glued it in place yet and I can always start over.
Thanks!
JLK

RE: FOCUS II ARF construction by-the-numbers

Using the Hyde mount, cut a 1/8 inch light ply disk out and glue it to the back of the engine mount with thick CA. Place the mount in the fuselage and drill two of the mount bolts holes. Push the engine/mount against the firewall and hold a spinner backplate in place to get a sense of engine position and general thrust alignment. Take the engine off the mount, slip the mount out and sand the backplate. Slip the engine mount back with the engine, put the two screws in and trial fit with cowl. If ok, do the final drilling and mounting of the hyde mount.

RE: FOCUS II ARF construction by-the-numbers

TW,

Throttle to rudder mix came after the FOCUS planes for me. I actually flew the FOCUS II at the NATS with no throttle to rudder mix, no rudder to aileron mix, and no rudder to elevator mix. That surprised me when I realized that! It flew pretty close but did end up putting some rudder to elevator/aileron mix in at a later date. However, I guess my rule of thumb now is to mix in whatever it takes to make the plane do what it needs to do. Its all a matter of reduced pilot workload. Throttle to rudder makes a lot of sense if you need it. I just can't remember that specifically, but I do know that every FOCUS I fly, I tell the pilot how good of a flying plane they have! Next contest we attend together in D2, I'll be happy to trim this for you.

RE: FOCUS II ARF construction by-the-numbers

Answering additional questions. In terms of fuel tank mounting, No pictures handy, but if I remember correctly I put two cross pieces 1/4x 1/2 bass and then used fuel tubing as rubber bands to hold the tank in place. I recall the throttle servo was a JR 368 mounted on the side of the fuselage either along the tank or in front of it. The canopy removed which was very convenient. I used #4 screws and inner nyrod yellow as the bushing for the screw to go in on the fuselage side. They never came loose but were easy to remove.

RE: FOCUS II ARF construction by-the-numbers

This Focus II thread is back to date by popular demand....

Although mine has been in the hands of a fellow club member. Lets see its been two years and I'm still waiting on him to keep his promise to become active in Pattern and join the circuit. Any case, CG on my Focus II to the best of my recollection was in the range of 7 1/4 to 7 3/8; just in front of the wing tube.